Thousands of people, some carrying signs reading "No to dictatorship!" and "Capriles for President", took part in marches against the unpopular leftist government of President Nicolas Maduro.

Addressing a crowd before Saturday's demonstration, which drew thousands, Capriles said "Nobody can disqualify the Venezuelan people".

Venezuela protesters marched through Caracas and cities across the country on Saturday, as the government's ban of Venezuela's top opposition leader from office breathed life into the disparate opposition and fueled the first sustained anti-government demonstrations since 2014.

The order from the national comptroller's office cited "administrative irregularities" including breaking contracting laws and improper management of donations, according to a copy of the ban.

Venezuelan police fired tear gas at anti-government protesters on Saturday as demonstrations against President Nicolas Maduro continued in the capital Caracas.

The opposition refers to the events as an "ongoing coup" by the government which has energised and united the normally fractious opposition. His supporters decried the move as another step toward dictatorship.

The protesters are demanding the dismissal of all seven Justices of the Venezuelan Supreme Court after the apex court issued a ruling on March 29 that all powers vested under the legislative body, the Venezuelan National Assembly, be transferred to the court itself, which is stacked with the government loyalists.

Over the last few days, authorities accused the opposition - and Capriles in particular - of fomenting violence and bloodshed by leading increasingly intense protests against Maduro.

"This thing that they just did to Capriles is the product of tyranny", Adel Rincones, 61, told AFP news agency.

"Every day, the government gives us more reasons to leave our homes and protest", said Paez, who earns less than $20 a month as a chemical engineer.

As the sea of protesters approached the headquarters of state-run PDVSA oil company, they were met by a curtain of eye-scorching tear gas and rubber bullets.

While she said she was hopeful the world is beginning to see there are injustices in Venezuela, her father, Carlos Paez, was more pessimistic.

He said the main aim of the protests is to call for elections.

Supporters of Maduro have also staged protests across the country this week. With both seemingly out of the running, the government may be trying to manipulate the electoral playing field to leave the opposition with less viable options should the government bow to pressure and call presidential elections before they're scheduled in 2018, analysts said.

Last year, the opposition launched an abortive attempt to force Maduro out of office by seeking to hold a recall referendum.

"However, it is a risky strategy that will probably backfire", Eurasia Group said in a report Friday.